1. Field of the Invention
The present invention relates to a high-recording density magnetic recording device and, more particularly, to a magnetic recording medium of a hard disk unit.
2. Background Art
Along with an increase in the recording density of a magnetic recording device, noise due to an disorder in the magnetized state of track edges arising in association with an increase in track density, a side-read phenomenon arising due to reading from adjacent tracks, damage to a magnetic recording medium due to a decreased floating amount of a magnetic head, and the like have become extremely critical issues. In order to solve these problems, there is an expectation for the realization of a discrete track medium the tracks of which are physically divided from one another.
In recent years, a study has been made of a discrete track medium and there is known a variety of materials, processes and the like used to physically fill up intertrack spaces (see JP Patent Publication (Kokai) Nos. 2006-196143 and 2006-92632). Since a concavo-convex shape remains on a surface of a recording medium if a refill material is formed on a convex portion of a track and a concave portion between tracks, the medium surface needs to be planarized. As a method for removing superfluous layers of resist and the refill material on the convex portion, there is known a liftoff method for removing the resist and the refill material adhering to the periphery of the resist using an organic solvent. In addition, a dry etching method, CMP and the like capable of selectively removing only the refill material on the convex portion have been applied on trial. As the dry etching method, there is known a method in which, for example, a stopper layer is formed on a magnetic recording layer and the entire medium surface including a concavo-convex shape is filled with the refill material. Next, only a mask material is selectively dry-etched by taking advantage of a etching rate ratio between the refill material and the mask material, in order to remove a superfluous amount of refill material formed on convex portions (JP Patent Publication (Kokai) No. 2006-196143).